Speed peripheral device classification information exchange and
- Information exchange
- Program query
- Program interrupt
- DMA mode
- Channel mode
Bus arbitration
- Centralized arbitration:
| Feature | |
| Chain query | Achieved by priority queuing interface circuit; Bus arbitration can be achieved by a certain priorities with little crossing a line, and it is easy to expand facilities The disadvantage is very sensitive to the fault interrogation circuit chain |
| Timed counter query | Like the chain query, the priority is fixed. Advantages: more flexible Cons: Too many line with |
| Independent way request | A queuing circuit Advantages: fast response, it takes less time; priority order control is very flexible. Disadvantages: design complexity |
- Distributed arbitration